V10

These petrol usually have fuel additives which help the engine stay carbon free(you can feel this around 26,000 km in petrol cars),i feel it is preferred you add the additives of your choice to the car when you full tank it, end of the day unleaded or premium "first concern here" in India is you get the right quality fuel & the right quantity as pumps as we all know are such a scam.So look into the petrol pump where you want to fill up first !

V10

some car models recommend premium petrol i remember seeing this on a camry.
at the end of the day it is your choice anyways, you can save money by filling in regular fuel and buying fuel additives of a good make to your tank once in a while. but do try using these premium fuels if you may and see which provides better fe and makes the engine run smooth.

Core Team

Almost a decade back when my car was new, I was very conscious and used to fill up premium petrol. Eventually moved to regular fuel and really did not feel much of a difference. Though some people have also reported slightly improved fuel efficiency etc. Now I have again bought a new car and was thinking about the same question. But I think I will stick with the normal fuel. Speaking in general sense, filling regular type of fuel is sufficient enough as long as it is unadulterated and prescribed by the car manufacturer. Adding further to what Prads said. Here is a related useful thread: http://www.theautomotiveindia.com/f...ating-short-fuelling-tricks-petrol-pumps.html

V10

Well, in my opinion, there isn't much difference between the both. It's almost the same. There wouldn't be any fuel gain but some people have told that it makes the engine a bit more smooth. Maybe it does, but some petrol pumps may cheat you (Check out 350Z's Link). So practically speaking sometimes even when you fill in the Premium one, it would be the normal petrol & hence you wouldn't notice the difference.

V4

@350Z: Very informative link, thanks so much !!
I think we should only fill petrol/diesel in HP/Indian Oil Authorized pumps. Any way how to recognise their authenticity/genuinity?
The reason being, in Mumbai/Thane area there are many pumps which only have a HP logo and a single pump. Rest of the petrol pump is just barren without any proper facilities.

V10

actually in india only premium fuels are nothing different except they have some additives, abroad fuels are regular 97octane and 100 octane. in india according to bs4 which i have read online premium fuels have to be 93octane which i don't see any pumps having they all are just 91 octane.
and as umang said above its hard to make out if you are getting the fuel with additives or not. while you can surely make out 97octane due to its color being different

heres an image of the petrols out abroad, 3 types and they are different from each other

V6

My cousin who uses a Getz & used to fill premium petrol for the last 8 years, changed to normal petrol last month & all of a sudden experienced an increase in the FE. It went up from 8 to 10 straight away!!!
Can someone explain that?

V10

. wow. you cousin is saving on fuel costs and getting more for the buck.
on my verna i have been filling in premium petrol, once or twice i filled in regular fe dropped by 1km/l but when i use the high octane fe increases by 2 km/l.

Suspended

Premium petrol means 98 Octane petrol
More octane = more efficient and the more carbon in the petrol makes a short layer of carbon (slippery layer) for pistons and cylinder area and car runs smooth and avoids over heating ( compared to normal petrol which is 91 octane)

Some cars have recommended 91 and some 98 .
High end sports cars use 98-100 octane fuel where as normal cars take 91 and some can take ethanol blend 94/95 octane fuel ( cheaper than 91 unleaded)